Accumulating evidence indicates that microRNA-146a (miR-146a), a well-known anti-inflammatory miRNA, acts as a negative feedback regulator of the innate immune response, but its role in modulation of inflammatory bowel disease (IBD) remains unclear and the issue related to the stability of exogenous miR-146a in blood is up in the air. In this study, extracellular vesicles (EVs) from cultured medium of bone-marrow mesenchymal stem cells (BMSCs) transfected with recombinant lentiviruses can serve as a stable delivery system and overexpress miR-146a, which significantly inhibited TNF receptor-associated factor 6 (TRAF6) and IL-1 receptor-associated kinase 1 (IRAK1) expression in TNBS-induced colitis of rats. Moreover, the increased phosphorylation levels of NF-κB p65 and IκBα were down-regulated by the administration of EVs containing miR-146a. Coupled with the associated influence of over-expressed miR-146a on phosphorylated proteins above, the production of inflammation factors such as tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6) and Interleukin-1β is apparently suppressed by this non-coding RNA. Collectively, these data elucidated that EVs containing miR-146a ameliorates experimental colitis caused 2,4,6‑trinitrobenzenesulfonic acid (TNBS) by targeting TRAF6 and IRAK1.
Keywords: Extracellular vesicles; IRAK1; Inflammatory bowel disease; TRAF6; miR-146a.
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